US3747470A - Spindle provided with an anti-vibration mechanism - Google Patents

Spindle provided with an anti-vibration mechanism Download PDF

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Publication number
US3747470A
US3747470A US00170554A US3747470DA US3747470A US 3747470 A US3747470 A US 3747470A US 00170554 A US00170554 A US 00170554A US 3747470D A US3747470D A US 3747470DA US 3747470 A US3747470 A US 3747470A
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US
United States
Prior art keywords
spindle
rotary shaft
viscous fluid
vibration
loading point
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US00170554A
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English (en)
Inventor
G Inoue
C Sato
M Tanaka
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NSK Ltd
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NSK Ltd
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Publication date
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Publication of US3747470A publication Critical patent/US3747470A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
    • B23Q17/09—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool
    • B23Q17/0952—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool during machining
    • B23Q17/0971—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool during machining by measuring mechanical vibrations of parts of the machine
    • B23Q17/0976—Detection or control of chatter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B41/00—Component parts such as frames, beds, carriages, headstocks
    • B24B41/04—Headstocks; Working-spindles; Features relating thereto
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T408/00—Cutting by use of rotating axially moving tool
    • Y10T408/76—Tool-carrier with vibration-damping means
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T409/00—Gear cutting, milling, or planing
    • Y10T409/30—Milling
    • Y10T409/304312—Milling with means to dampen vibration

Definitions

  • ABSTRACT A spindle has its intermediate portion rotatably surrounded by a journal box and journalled in radial bearings provided in the journal box.
  • a thrust bearing for absorbing the thrust load of the spindle is further provided, and the spindle has a flanged portion corresponding to the thrust bearing and inserted therein.
  • a viscous fluid film forming mechanism is provided to attenuate the self-excited vibration which may occur in the spindle during its operation.
  • the viscous fluid film forming mechanism is disposed around the spindle between the bearing portion and the loading point of the spindle, thereby attenuating the vibration of the spindle and ensuring smooth rotation thereof.
  • This invention relates to a spindle for use with machine tools such as lathes and grinders or with measuring instruments, and more particularly to a spindle provided with an improved mechanism for preventing a self-excited vibration of the spindle.
  • the viscous fluid film forming mechanism provided according to the present invention is directed to a function different from that of the bearing, that is, it utilizes the damping effect of viscous fluid to attenuate the vibration and accordingly enhance the performance of the spindle.
  • the vibration amplitude of the spindle tends to show a marked increase in the portion of the spindle ranging from the radial bearing adjacent the loading point toward the loading point.
  • the viscous fluid film forming mechanism should effectively be provided at a location as near as possible to the loading point, but the general performance of the spindle is governed chiefly by the correlation between the dynamic and the static rigidity of the spindle and an extreme unbalance of such correlation may adversely affect the general performance of the spindle.
  • the viscous fluid film forming mechanism be disposed within a journal box having bearings contained therein and the location of the mechanism be as close as possible to the loading point of the spindie.
  • a viscous fluid film forming mechanism of the present invention may achieve a full effect, it is necessary to ensure the presence of the vis cous fluid to at all times around the spindle portion surrounded by such mechanism, although the viscous fluid need not particularly be circulated under presure.
  • the present invention includes a rotary shaft having a tool such as grinding wheel or cutting tool attached to one end thereof, a journal box surrounding the intermediate portion of the rotary shaft and radial and having thrust bearings forjournalling the rotary shaft, and a viscous fluid film forming mechanism disposed between the bearing portion and the tool or the loading point so as to prevent any self-excited vibration of the rotary shaft.
  • Such a viscous fluid film forming mechanism may be realized by providing a cylindrical member around the rotary shaft with a slight clearance maintained between the inner side wall of the cylindrical member and the outer side wall of the rotary shaft, and providing the cylindrical member with at least one passage radial with respect to the rotary shaft so that viscous fluid supplied from outside the journal box may be passed through the radial passage into the slight clearance between the rotary shaft and the cylindrical member within the viscous fluid film forming mechanism, thereby forming in the slight clearance a film of viscous fluid which ensures smooth rotation of the rotary shaft and highly efficient cutting or grinding work.
  • FIG. 1 is a front elevation, in cross section, of the spindle assembly according to the present invention.
  • FIG. 2 is an enlarged cross-sectional view of the viscous fluid film forming mechanism taken along lines b-b' of FIG. 1.
  • FIG. 3 is a enlarged front view of the same mechanism taken along lines a-a of FIG. 1.
  • FIG. 4 is a half of a logarithmic graph obtained by plotting the vibration amplitude of the spindle as analyzed by a computer and showing the absolute displacement of the exciting point for a varying frequency of vibration occurring at the exciting point, wherein the abscissa represents the frequency of vibration.
  • FIG. 5 is a half of a logarithmic graph obtained by plotting the vibration amplitude of the spindle as analyzed by a computer and showing the real part of displacement of the exciting point for a varying frequency of vibration occurring at the exciting point, wherein the abscissa represents the frequency of vibration.
  • FIG. 6 is a graph obtained by plotting the vibration amplitude of the spindle as analyzed by a computer and showing a typical curve representing the vibration amplitude at various points of the spindle in the axial direction thereof for an exciting force of 1 kg imparted at the exciting point.
  • a rotary shaft 1 has a grinding wheel 2 attached to one end thereof by means of a bolt 3, and extends through a journal box 4.
  • the rotary shaft 1 further has a flanged portion 11 for absorbing a thrust load of the rotary shaft and which is formed in the intermediate portion thereof toward the grinding wheel 2.
  • the rotary shaft 1 has a somewhat smaller diameter at its opposite end portions'than at its intermediate portion, and the opposite end portions of the shaft 1, together with the journal box 4, define sealing portions 12 and 13 for blocking leakage of viscous lubricant fluid.
  • the journal box 4 includes two radial bearing portions 5 and 6 for absorbing a radial load and a thrust bearing portion 7 for absorbing a thrust load.
  • the radial bearing portions 5 and 6 comprise similarly shaped pockets 5], 61 and sealing portions 52, 53, 62, 63, the pockets 51 and 61 each being formed with a plurality of fluid supply passages (not shown). Adjacent to the respective sealing portions there are formed fluid discharge passages 35, 55 and 45, 65.
  • the thrust bearin portion 7 is so formed as to define a slight clearance and pockets between itself and the thrust load flange 11 on the rotary shaft 1.
  • a mechanism for forming a film of viscous fluid to attenuate the vibration of the rotary shaft is generally designated by reference numeral 9 and provided in the journal box 4 adjacent to and axially outwardly of the thrust bearing portion 7.
  • the mechanism 9 comprises a cylindrical member 91 disposed so as to maintain a slight clearance with respect to the rotary shaft 1 and having six radial passages 92a, 92b, 92c, 92d, 92c and 92fformed therein to supply viscous fluid therethrough to the clearance between the cylindrical member 91 and the rotary shaft 1.
  • the number of such radial passages and the inner diameter of the cylindrical member 9 may be suitably determined by the type and required amount of the viscous fluid in use.
  • the mechanism 9 for forming a film of viscous fluid constitutes an essential part of the present invention, and the supply of viscous fluid to this mechanism will now be described.
  • Viscous fluid under pressure is introduced from outside into the journal box 4 through an inlet 16.
  • the viscous fluid introduced under pressure through the inlet 16 is passed through a flow rate throttle means 17, where the pressure of the fluid is reduced to a level slightly above the atmospheric pressure and part of such fluid is passed through a point 92a" into an elongated groove 18 (FIG.
  • the mechanism 9 is located in the journal box 4 at a position near the grinding wheel 2 and forwardly of the bearing portions, as shown, in order that a rotational motion of the spindle which will generally result in a high grinding performance may be provided even with some sacrifice of the static rigidity of the spindle.
  • the selfexcited vibration of the spindle from the varying load imparted thereto by the work-piece can be attenuated by the viscous fluid supplied to the clearance between the cylindrical member 91 of the viscous fluid film forming mechanism 9 and the rotary shaft 1, thereby ensuring smooth rotation and high grinding performance of the spindle.
  • the spindle of the present invention provides a greatly improvedresistivity to vibration only at the slight sacrifice of the static rigidity thereof, and generally achieves a considerably enhanced performance.
  • the spindle of the present invention warrants its use as a spindle for high precision work. If such a spindle is employed as the operating rotary shaft of a lathe or a grinder, it will not only improve the critical limit of chattering but also enable high-speed grinding operation and accordingly greatly increase the efficiency of operation.
  • the reduction in the static rigidity is so small that its influence upon the workpiece is negligible.
  • the highly improved resistivity to vibration is useful to reduce the wear of the grinding wheel or the cutting tool and this further leads to an advantage that the dressing of the grinding wheel or correction of the cutting tool can be made less frequent.
  • the bearings of the spindle have been shown as the fluidtype, but they may alternatively be of the roller type to attain the same effect as described above if the viscous fluid film forming mechanism for attenuating the vibration is located toward the loading point forwardly of the roller bearings.
  • narrow circular grooves may be provided to uniformly supply the viscous fluid into the slight clearance between the rotary shaft and the cylindrical member.
  • pockets may be provided at the outlet of each of the radial passages to provide a uniform distribution of viscous fluid into the slight clearance.
  • the dotted-line curve illustrates the absolute displacement at the exciting point as analyzed by a computer when the spindle of the present invention is not rotated but vibrated at a varying frequency with an amplitude of the force of 1 kg while a film of viscous fluid is formed to attenuate the vibration.
  • the solid-line curve represents the absoute displacement at the exciting point when the viscous fluid forming mechanism is not operatedin the spindle of FIG. 1. It is seen that the vibration of the spindle differs markedly depending on whether the film of viscous fluid is formed or not.
  • the absolute displacement sharply increases for an excited vibration of 900 Hz or near, whereas in the spindle of the present invention the increase in absolute displacement is very small and this means that the film of viscous fluid contributes greatly to improve the resistivity to vibration.
  • FIG. 5 graphically illustrates the real part of displacement of the exciting point calculated for the spindle of FIG. 1 on the same condition as that of FIG. 4.
  • the solid-line curve indicates the displacement of the spindle when the viscous fluid film forming mechanism is not operative
  • the dotted-line curve shows the displacement when the viscous fluid film forming mechanism is operative in the spindle of the present invention.
  • the limit of the condition under which chattering occurs as the result of the self-excited vibration is determined by the negative peak value in FIG. 5. If no negative component exists, no chattering will occur.
  • the spindle of the present invention shows some negative component, but such negative component may be reduced by increasing the axial dimension of the viscous fluid film forming mechanism and decreasing the radial dimension of the clearance.
  • the values of these factors must be suitably selected in accordance with the conditions under which the spindle is used, and with the general performance of the spindle taken into consideration.
  • FIG. 6 illustrates the typical curve representing the variation occurring in the longitudinal vibration amplitude of the spindle when an exciting force of 1 kg is imparted at the exciting point. It can be clearly seen from this curve that the vibration amplitude of the spindle is not so much increased in the portion from the longitudinal center toward the opposite end to the loading point but is greatly increased in the portionfrom the center toward the loading point. Thus, it will readily be appreciated that the self-excited vibration of the spindle and the amplitude of the vibration may advantageously be minimized or reduced if the viscous fluid film forming mechanism for attenuating the vibration is provided between the bearing portion of the spindle and the loading point and as near as possible to the latter.
  • a spindle provided with an anti-vibration mechanism comprising a rotary shaft, a journal box rotatably supporting said rotary shaft and surrounding the intermediate portion thereof, radial bearings provided in said journal box for journaling said rotary shaft, a thrust bearing provided in said journal box for absorbing the thrust load of said rotary shaft, said rotary shaft being formed with a flanged portion adapted to be inserted into said thrust bearing, a supply of viscous fluid and a mechanism adapted to receive said viscous fluid for forming a film of viscous fluid, said mechanism comprising a cylindrical member formed with a bore therein and disposed around said rotary shaft between the loading point of said spindle and one of said bearings adjacent to said loading point to maintain a slight clearance with respect to said rotary shaft, said cylindrical member having at least one passage formed therein radially with respect to said rotary shaft for supplying viscous fluid therethrough into said clearance.
  • An apparatus for hydrodynamically damping selfexcited vibration in a spindle comprising in combination:
  • journal box for rotatably supporting said rotary shaft
  • a tool means mounted on one end of said rotary shaft to contact with a work piece thereby constituting a loading point of said rotary shaft;
  • an anti-vibration mechanism formed with a bore slightly larger than the diameter of said rotary shaft and disposed in an alignment therewith such that a clearance between the outer surface of said rotary shaft and the surrounding surface of said bore is maintained said mechanism being positioned between the loading point of said rotary shaft and one of said bearings arranged closest to said loading point;
  • said anti-vibration mechanism comprises a cylindrical member having a plurality of radial passages formed therein for supplying viscous liquid therethrough and a plurality of oblique passages, each of said oblique passages being in fluid communication with a corresponding one of said radial passages and a groove which is formed in the outer periphery of said cylindrical member for distributing said viscous fluid through a throttle means to each of said radial passages through each of said corresponding oblique passages, said oblique passages being oblique with respect to the axial direction of said cylindrical member.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Turning (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)
  • Auxiliary Devices For Machine Tools (AREA)
US00170554A 1970-08-15 1971-08-10 Spindle provided with an anti-vibration mechanism Expired - Lifetime US3747470A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10240670A JPS54547B1 (enrdf_load_stackoverflow) 1970-08-15 1970-08-15

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US3747470A true US3747470A (en) 1973-07-24

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3954309A (en) * 1974-11-21 1976-05-04 The Hutson Corporation Hydrodynamic bearings for vibratory mechanisms
US4222692A (en) * 1977-11-15 1980-09-16 George Fischer Aktiengesellschaft Machine tool feed system with adjustable bearings
US4288165A (en) * 1979-08-15 1981-09-08 The Hutson Corporation Vibratory actuator incorporating hydrodynamic journal bearing
USRE30919E (en) * 1974-08-29 1982-05-04 Pennsylvania Crusher Corporation High-speed rotating crushing machinery
US4387539A (en) * 1981-03-30 1983-06-14 The Hutson Corporation Vibratory actuator
DE3406826A1 (de) * 1983-03-04 1984-09-06 Cincinnati Milacron Industries, Inc., Cincinnati, Ohio Gedaempfter werkzeug-revolverkopf
FR2543032A1 (fr) * 1983-03-21 1984-09-28 Cincinnati Milacron Ind Inc Dispositif d'amortissement de la broche d'une machine-outil
FR2547227A1 (fr) * 1983-06-08 1984-12-14 Cincinnati Milacron Ind Inc Amortisseur pour glissieres de machines-outils
US4664536A (en) * 1985-11-25 1987-05-12 Cincinnati Milacron Inc. Compound damper system
EP0272720A1 (en) * 1986-11-24 1988-06-29 Koninklijke Philips Electronics N.V. Shaft support comprising static fluid bearings
WO1990007071A1 (en) * 1988-12-22 1990-06-28 National Research Development Corporation Mechanical devices and structures
US5700092A (en) * 1994-05-04 1997-12-23 Aesop, Inc. Integrated shaft self-compensating hydrostatic bearing
US20040234351A1 (en) * 2001-10-09 2004-11-25 Franco Mazza' Tool-holding system for high-accuracy calibration of holes
US20110070043A1 (en) * 2009-09-08 2011-03-24 Haas Automation, Inc. Dampened spindle cartridge and spindle adaptor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6790574B2 (ja) * 2016-08-12 2020-11-25 株式会社ジェイテクト 主軸装置と、該主軸装置を備えた研削盤

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3030744A (en) * 1960-03-08 1962-04-24 Harig Mfg Corp Air film bearing for machine tools
US3058785A (en) * 1959-09-21 1962-10-16 Lucas Industries Ltd Gas lubricated bearings
US3493273A (en) * 1968-02-09 1970-02-03 Babcock & Wilcox Co Hydrostatic machine tool spindle

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3058785A (en) * 1959-09-21 1962-10-16 Lucas Industries Ltd Gas lubricated bearings
US3030744A (en) * 1960-03-08 1962-04-24 Harig Mfg Corp Air film bearing for machine tools
US3493273A (en) * 1968-02-09 1970-02-03 Babcock & Wilcox Co Hydrostatic machine tool spindle

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE30919E (en) * 1974-08-29 1982-05-04 Pennsylvania Crusher Corporation High-speed rotating crushing machinery
US3954309A (en) * 1974-11-21 1976-05-04 The Hutson Corporation Hydrodynamic bearings for vibratory mechanisms
US4222692A (en) * 1977-11-15 1980-09-16 George Fischer Aktiengesellschaft Machine tool feed system with adjustable bearings
US4288165A (en) * 1979-08-15 1981-09-08 The Hutson Corporation Vibratory actuator incorporating hydrodynamic journal bearing
US4387539A (en) * 1981-03-30 1983-06-14 The Hutson Corporation Vibratory actuator
US4491044A (en) * 1983-03-04 1985-01-01 Cincinnati Milacron Inc. Damped tool turret
DE3406826A1 (de) * 1983-03-04 1984-09-06 Cincinnati Milacron Industries, Inc., Cincinnati, Ohio Gedaempfter werkzeug-revolverkopf
FR2543032A1 (fr) * 1983-03-21 1984-09-28 Cincinnati Milacron Ind Inc Dispositif d'amortissement de la broche d'une machine-outil
FR2547227A1 (fr) * 1983-06-08 1984-12-14 Cincinnati Milacron Ind Inc Amortisseur pour glissieres de machines-outils
US4664536A (en) * 1985-11-25 1987-05-12 Cincinnati Milacron Inc. Compound damper system
EP0272720A1 (en) * 1986-11-24 1988-06-29 Koninklijke Philips Electronics N.V. Shaft support comprising static fluid bearings
WO1990007071A1 (en) * 1988-12-22 1990-06-28 National Research Development Corporation Mechanical devices and structures
US5700092A (en) * 1994-05-04 1997-12-23 Aesop, Inc. Integrated shaft self-compensating hydrostatic bearing
US20040234351A1 (en) * 2001-10-09 2004-11-25 Franco Mazza' Tool-holding system for high-accuracy calibration of holes
US7134818B2 (en) * 2001-10-09 2006-11-14 Sumen Italia S.R.L. Tool-holding system for high-accuracy calibration of holes
US20110070043A1 (en) * 2009-09-08 2011-03-24 Haas Automation, Inc. Dampened spindle cartridge and spindle adaptor
US8845245B2 (en) * 2009-09-08 2014-09-30 Haas Automation, Inc. Dampened spindle cartridge and spindle adaptor

Also Published As

Publication number Publication date
JPS54547B1 (enrdf_load_stackoverflow) 1979-01-11

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